Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual categoria é Matthew Barton?
 ###Tabelas: CREATE TABLE minister_for_community_safety_and_legal_affairs (minister_for_community_safety_and_legal_affairs_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Entered office VARCHAR, Left office VARCHAR, Party VARCHAR, First Minister VARCHAR) CREATE TABLE slovenian_open (slovenian_open_id AUTO_INCREMENT PRIMARY KEY, Year Location VARCHAR, Mens Singles VARCHAR, Womens Singles VARCHAR, Mens Doubles VARCHAR, Womens Doubles VARCHAR) CREATE TABLE singles:_6_3_titles_3_runner-ups (singles:_6_3_titles_3_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Date VARCHAR, Category VARCHAR, Surface VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE season_5:_2005 (season_5:_2005_id AUTO_INCREMENT PRIMARY KEY, Series Ep. VARCHAR, Episode INT, Netflix VARCHAR, Segment A VARCHAR, Segment B VARCHAR, Segment C VARCHAR, Segment D VARCHAR) CREATE TABLE during_the_season (during_the_season_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Outgoing manager VARCHAR, Manner of departure VARCHAR, Date of vacancy VARCHAR, Replaced by VARCHAR, Date of appointment VARCHAR, Position in table VARCHAR)  
SELECT Category FROM singles:_6_3_titles_3_runner-ups WHERE Opponent = matthew barton